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EEG Recording Guideline for CVBE

In this goideline document, you will be introduced to information about how to conduct an EEG experiment in our lab. This notebook is designed for an anyone regardless of their background. Throughout the document, you may find images, external links for videos, references for papers and books which you are encouraged to take your time to work on for building up your knowledge base on EEG research. Please visit those links in case you believe your are not comfortable with the specific topic. Below, you can find a list of chapter that this guideline covers. You can read all document from the beginning to the end but also it is possible to directly select a specific chapter and go thourgh it ince case you believe you already have the information in some parts.


Tutorial Parts

1.What do we have? Our Setup

2.Procedure

3.Termination and Cleaning

4.Troubleshooting

5.Data Analysis

6.Useful Resources

Bonus: Good Practices in EEG Research

References


1.What do we have? Our Setup

In this part of the notebook, you could find a list of EEG recording materials we have at CVBE, with photographs of each item, their quantities and information about where can you find them.

-Daily Equipment: This is the list of EEG equipment that we use daily. Ideally, this list should be updated once any change is done to the inventory.

-Backup Equipment: This list contains the equipment we had at the EEG room as bakcup for our daily use.

-Complete Inventory (Company's Deliver): This is the complete list of inventory that BrainProducts delivered to the lab.


Figure 1. Symbolic EEG Hyperscanning Setup we have Brain_Amp_Hyper_Setup_Figure.png

The image shows the figurative setup we have for 2-subjects hyperscanning. There are 2 amplifiers connected to the electrodes from each subject and most importantly, have unique REF (reference) and GND (Ground) electrodes for each subject. Each individual has its own electrode box. Both amplifiers are connected to a single USB2 box which is connected to the data acquisition computer. (Images are taken from this paper)


Figure 2. Same setup with actual photographs of the gadgets:

Brain_Amp_Hyper_Setup_Actual.png

We have the same setup at our lab, a photo of our own setup will be also added soon.


Figure 3. Schematic Illustration of the Hyperscanning Setup from BrainProducts' Website: Hyperscanning_BrainAmps_SetUp-1.png

Note: Electrodes from 2 participants are individually connected to their own ControlBoxes. Then, ControlBoxes are connected to their own amplifiers. The stimuli presentation computer is connected to the TriggerBox which in return connected to the USB2 Adaptor. Finally, 2 amplifiers are also connected to the USB2 Adaptor which is connected to the data acquisition computer. Triggers and data from 2 subjects are fully synchronized within the USB2 Adaptor.

2.Procedure

2.0.Preparation

1. Send a reminder email 1-2 days before the study. Include the time, date, and location of the testing session, as well as information about the general testing procedure (e.g., what to expect, how long it will take, etc.). Include a list of reminders, such as: “The procedures require us to put gel in your hair, which may get on your clothing. Do not wear any clothing that may be harmed by the gel, or you would not wish to get gel on (although the gel is water soluble). If you have an important event immediately after the testing session, it may be best to reschedule. Participants need to be completely awake during the experiment, so please have sufficient amount of sleep before arriving. Arrive with clean, dry hair, and remove all ponytails, braids, wigs, extensions, hair clips, hats, etc., prior to arrival.” a. If a participant arrives wearing inappropriate clothing, have the person wear a T-shirt over the clothing to avoid damage.

2. Lay out as much of the equipment prior to the subject’s arrival as you can. This includes the SuperVisc gel, syringes, syringe tips, towels, electrode collars, gloves, tape measure, and alcohol wipes

  1. Unwrap a sterile Luer-Lock syringe.

  2. Use the syringe to draw up approximately 10 ml of gel from the SuperVisc jar, then screw on the syringe tip. Gently push down on the plunger to squeeze out any air bubbles over the sink or trash can. If you are working with a partner, it can be more efficient to prepare two syringes (each with half as much gel), rather than a single syringe. a. 10 ml of gel should be enough for 32 electrodes. If you are using 64 electrodes, you can either refill the syringe or prepare additional syringes in advance. If refilling the syringe, be sure to maintain proper sanitation by using a clean, uncontaminated syringe to transfer the gel; do not use a syringe that has previously contacted the subject’s scalp. b. Any Luer Lock syringes and syringe tips that come in contact with the subject must be discarded or disinfected before re-use.

  3. If the subject has participated before and you know their cap size, Electrode Application steps 6-9 can also be completed prior to arrival.

2.1.Getting Participants Ready

Prior to every experiment, there is a list of things to be checked. First, the materials for the EEG recording should be carefully examined and made sure that everything is ready, usable and enough number of materials are at hand. In case of any problems with the BrainProducts' gadgets, please visit to the user manual of the setup. In case you are not sure about what is wrong, please refer to the Jimmy.

Next, you need to make sure that the participants are still available for the experiment. Make sure to contact with them the day before the recording, via an e-mail, provide time and date information but also, information about don't do's. Once the setup and participants are ready, the initial step of preperation procedure is implementing the electrodes. We have two groups of electrodes: active and external. Active electrodes are also referred to as EEG electrodes, which are the electrodes that actually collects the signal. External electrodes on the other hand, are those which we use for various reasons other than scalp EEG. First, we have EOG electrodes that will be placed around the ee of the participants to measure electrical activity of the eye muscles in order to remove this activity from our EEG data (see Data Analaysis for further information on data cleaning). Secondly, we have REF, reference, electrodes that are placed on the mastodi of the participants. As their name suggest, these electrodes are used to be a reference point for our signal, near to the scalp (source of the EEG) but minimally or none influenced by the EEG signal.

Once everything is ready for the setup, you can move to the electrode implementation phase as below.

How to implement the electrodes?

Figure 4. What we need? A visual start

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Necassary Equipment and Their Functions:


Visual Guide to Electrode Implementation:

And in the darkness, bind them: Connecting Things Together

Once the electrode placement for each participant, including external ones, is done, it is time to move to the next step of EEG recording. On this step, the EEG setup should be combined together to getting ready for the actual recording. There are several steps to be done:

1. Connect the electrodes to the control box:

2. Connect the control box to the amplifier:

3. Connect the amplifier to the BUA

4. Connect the Trigger Box to the BUA

5. Connect the BUA to the Data Acquisition Computer

2.2.Checking Data Quality

2.3.Starting Session and Monitoring

3.Termination and Cleaning

4.Troubleshooting

5.Data Analysis

6.Useful Resources

6.1.Background of EEG

In case you would like to start with a "zero-to-hero" perspective on EEG, here are some useful resources for EEG research:

6.2.EEG Data Analysis

In case you would like to have a hands-on learning experience about EEG data analysis, we strongly encourage you to visit Mike Cohen's Personal Website where you can find books and video lectures.

Bonus: Good Practices in EEG Research

References